As building materials which are used as housing instruments and interior materials, for example, furniture, desk tops, various counters, doors, etc., there are in general widely used decorative plates obtained by shaping a synthetic resin based material, for example, thermosetting resin decorative plates, e.g., melamine resin decorative plates, etc.
Hitherto, a thermosetting resin decorative plate having a concave-convex shape on the surface thereof includes one obtained by forming a concave-convex shape by an embossing die or a resin concave-convex sheet and one obtained by forming a concave-convex shape by a shaping sheet. However, when an embossing die having a concave-convex shape formed thereon is used, since it is necessary to subject the die to a surface treatment by blasting, etching, etc., there are generated limitations in minuteness of a concave-convex shape and a pattern. Furthermore, at the time of manufacturing a thermosetting resin decorative plate, an expensive template and a reserve template are necessary, and time and a load of expenses for the preparation of a decorative plate increase, and therefore, the manufacturing cost largely increases, resulting in rendering a product expensive. Also, in case of a resin concave-convex sheet, since a thermosetting resin decorative plate is hardly peeled after the resin has been cured, it is necessary to interpose an aluminum foil, a polypropylene film, etc. in a space with a template, it is very difficult to sharply form a minute concave-convex pattern.
Meanwhile, in recent years, according to the consumer's orientation toward quality goods, an air of luxuriousness is also required for furniture, desks, interior materials, etc., and those having an appearance capable of giving an air of luxuriousness are also desired in decorative plates to be used therefor. For that reason, it is important to impart a texture, and various methods for imparting a delicate concave-convex shape to a decorative plate are proposed.
For example, there is proposed a shaping sheet having a concave-convex shape with an ionizing radiation curable resin provided on the surface of a base material sheet, which is able to faithfully reproduce a desired pattern shape by providing a crosslinking density such that when the shaping sheet is peeled, the concave-convex shape is not broken, and which can be repeatedly used (see Patent Document 1, claim 1). However, in preparing a shaping sheet, a step of peeling it from a roll concave plate is mediated, and therefore, when the concave part is thin, there is a limitation in expressing the concave-convex shape. Also, according to this method, when the concave part is thin, there is involved a problem that unevenness does not clearly appear; whereas when the concave part is thick to some extent, though a concave-convex pattern is obtained on the base material surface, a convex part of a height of the raised part or more is generated, and for example, in case of a woodgrain pattern, there are involved problems that no realist feeling is present and that appearance and touch feeling are poor.
Furthermore, there is proposed a shaping sheet in which a concave-convex layer is formed on the surface of a base material sheet using a resin composition composed of an inorganic filler and a binder resin, and only the resin composition for forming a fine concave-convex layer which is coated on a design pattern formed of a liquid-repellent resin is repelled to form the concave-convex layer (see Patent Document 2, claims). However, there are involved problems that since the concave-convex layer is formed by repelling the resin composition for forming a concave-convex layer, the design by a concave-convex shape is lacking in stability and that since aging of a certain period of time is required for curing the concave-convex layer, it takes a very long time to prepare the shaping sheet so that it is impossible to rapidly respond to diversified needs of consumers.
[Patent Document 1] JP-A-7-164519
[Patent Document 2] JP-A-5-92484